cp's OEIS Frontend

A209461 Number of nX4 0..6 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..6 introduced in row major order.

%I A209461 #9 Jul 22 2025 21:44:10
%S A209461 15,700,107472,26142922,8012278798,2694404849980,937020001725427,
%T A209461 329698685591776814,116478477506382991586,41208120649861041328594,
%U A209461 14585813504694387764542258,5163586671381153188498288526
%N A209461 Number of nX4 0..6 arrays with every 2X2 subblock containing exactly one value repeat, and new values 0..6 introduced in row major order.
%C A209461 Column 4 of A209465
%H A209461 R. H. Hardin, <a href="/A209461/b209461.txt">Table of n, a(n) for n = 1..210</a>
%F A209461 Empirical: a(n) = 445*a(n-1) -16724*a(n-2) -6829442*a(n-3) +425591990*a(n-4) +24184676824*a(n-5) -2003243723592*a(n-6) -13763458467748*a(n-7) +3056362447165464*a(n-8) -21627878272249304*a(n-9) -2029212853652220216*a(n-10) +28420879571353866736*a(n-11) +629172550069243165424*a(n-12) -12639966451485066876640*a(n-13) -86182077853495170865408*a(n-14) +2735491326134206206383232*a(n-15) +2903173644048356636793984*a(n-16) -330995326037510772586662272*a(n-17) +548472275306500667348231040*a(n-18) +24119429078647666871628591360*a(n-19) -73980455487855760024028638464*a(n-20) -1106883636299545527909945293312*a(n-21) +4138072035906627647242997043200*a(n-22) +33143037572510239567740461978624*a(n-23) -127626560667065292804603082412032*a(n-24) -670244550685808176819553023221760*a(n-25) +2324071862180088735462417275084800*a(n-26) +9301947054683461351288165219942400*a(n-27) -25275371467923494811033198815182848*a(n-28) -86564162243269555830237302308208640*a(n-29) +160836131708205440217973980668624896*a(n-30) +508044890654947403039030776702173184*a(n-31) -580869391543190835146635714165211136*a(n-32) -1736356953978805111720511551328747520*a(n-33) +1196798002553675840426691890553815040*a(n-34) +3180957198473295518827632622829568000*a(n-35) -1545683172554581444784017951948800000*a(n-36) -2843829257934103086795545640960000000*a(n-37) +1252556305409710302651482112000000000*a(n-38) +967672505058411923531366400000000000*a(n-39) -457884355579447187865600000000000000*a(n-40) for n>41
%e A209461 Some.solutions.for.n=4
%e A209461 ..0..1..0..0....0..0..0..1....0..1..1..0....0..0..0..0....0..1..2..1
%e A209461 ..0..2..1..2....2..3..1..2....2..0..2..0....1..2..1..2....1..2..0..0
%e A209461 ..0..1..3..1....0..0..3..1....1..2..3..2....0..2..3..1....0..0..3..4
%e A209461 ..0..2..2..2....1..2..0..3....0..0..0..3....0..1..1..4....1..2..0..3
%K A209461 nonn
%O A209461 1,1
%A A209461 _R. H. Hardin_ Mar 09 2012